Strokes are very common in the United States and occur more in the elderly. The number of strokes is likely to double in the next 50 years. Many stroke survivors are sedentary and have a poor dietary intake, which results in abnormalities in fuel utilization (eg carbohydrate versus fat). This study will examine the effects of dietary modification and treadmill training on fuel utilization and physical function. We will study skeletal muscle oxidative stress in chronic stroke patients and the ability to employ dietary modification and exercise training to reverse these abnormalities in this ethnically diverse population.
In acute stroke settings, it is known that energy imbalance is associated with poorer rehabilitation and functional outcomes, and importantly, increased risk of institutionalization. However, nutrition and eating habits of chronic stroke rehabilitative care have received very little consideration, especially if the survivor is living in a free living environment. Studies have shown deficiencies in energy and protein intake versus recommendations in chronic stroke survivors. Perry et al. found ~7% of chronic stroke survivors were at moderate and ~5% at high nutritional risk. Although little is known regarding total daily energy expenditure and dietary intake in chronic stroke, energy and macronutrient imbalance may have a profound impact on stroke recovery and risk of development of chronic disease and recurrent stroke by altering substrate oxidation and result in systemic and tissue level oxidative stress. Conversely, cardiovascular disease risk increases with excess calorie and fat intake and two-thirds of stroke survivors are overweight or obese. In obese, non-stroke populations, energy dense, high fat meals are associated with increases in plasma oxidative stress markers. Oxidative stress can lead to mitochondrial damage and abnormal accumulation of metabolite intermediates and lipid accumulation in non-adipose tissues, which can impair heart function, increasing CVD and stroke recurrence risk.
- Treadmill Exercise Behavioral
Intervention Desc: Training will be started conservatively with a goal of 15 minutes total duration at 40-50% HRR. Training target HR = %(HRmax - HRrest) + HRrest. HR max is defined as peak HR based on 2 maximal exercise tests at baseline. Individuals unable to walk continuously will exercise intermittently for several minutes as tolerated, with rest intervals, and advanced as tolerated with HR, blood pressure monitoring, and Borg Perceived Exertion to assess subjective cardiopulmonary exercise tolerance, as previously described. Treadmill training velocity will advance as tolerated by week 6 to a target intensity of 70-80% maximal HRR. Duration will similarly advance to a target of 30 minutes by week 6. Following week 6, the progressive training protocol will continue with attempts to increase velocity on a weekly basis and increase duration by 5 minutes bi-weekly to peak at 50 minutes. After week 6, the target HR goal will be 75-85% of HRR as tolerated by the subject. ARM 1: Kind: Experimental Label: Treadmill Exercise Description: Six months of treadmill training
- Stretching (control) Behavioral
Intervention Desc: Stretch controls will be enrolled in supervised stretching program for 2 days/week for 1 hour sessions. The stretch program will focus on basic mobility skills, including balance, endurance, sit-to-stand, weight shifting, leg strength, and truncal stability-coordination. Stretching will be done in groups up to 6 participants. Exercises will be performed in standing, seated, and lying positions. A log book on the stretching exercise participation and progression will be maintained and reviewed by the instructor with the participant at each session. ARM 1: Kind: Experimental Label: Stretching (Control) Description: Six months of stretching
- Allocation: Randomized
- Masking: Open Label
- Purpose: Treatment
- Endpoint: Efficacy Study
- Intervention: Parallel Assignment
|Type||Measure||Time Frame||Safety Issue|
|Primary||the change in total daily energy expenditure||measured at baseline and following 6 months of treadmill training or stretching (control)||No|
|Secondary||the change in substrate oxidation||measured at baseline, after 2 weeks of dietary education, and following 6 months of treadmill training or stretching (control)||No|
|Secondary||the change in tissue oxidative stress||measured at baseline and following 6 months of treadmill training or stretching (control)||No|